1. Field of the Invention
The present invention relates to a clean room used to fabricate semiconductor devices and a clean room remodeling method used to remodel an existing clean room to provide a clean room with a different specification if necessary, and to remodel a general passage or room adjacent to a clean room to provide a clean room.
2. Description of the Prior Art
Semiconductor devices are extremely sensitive to dusts such as dust particles in their fabrication process. Hence, it is customary that semiconductor devices are variously processed on the fabrication line in a clean room. A clean room generally comprises a working room used to fabricate semiconductor devices in actual practice, a supply chamber built in a space above the ceiling of the working room to supply the air to the working room, a dust-collecting filter for removing dust particles from the air supplied to the working room, a grated panel built on the floor of the working room to let in the air, a return chamber for returning the air from the grated panel through a circulation duct and an air conditioner for circulating the air in the sequential order of the supply chamber, the working room and the return chamber and which is also used to adjust the temperature and the humidity of the air.
A cleanliness of clean room changes depending upon factors such as an integration degree of semiconductor devices manufactured therein. A variety of dust-collecting filters are used in response to a required cleanliness. As a dust-collecting filter, there are selectively employed a HEPA (High Efficiency Particulate Air) filter and a ULPA (Ultra Low Penetration Air) filter, etc. Japanese laid-open patent publication No. 5-149591 and Japanese laid-open patent publication No. 3-177732, for example, described such clean room.
So far a new clean room is required, it is customary that a new clean room is built in a vacant lot, including a foundation work. The reason for this will be described. As the semiconductor technologies are advanced rapidly, requirements concerning the specifications of the new clean room become severer than those of the prior art. Hence, it was rather easy to build a new clean room including the setting of blow capacities of air conditioners and a layout of places in which dust-collecting filters are located.
However, recently, a difficulty in maintaining a labor power and obtaining a building lot increases, and a cost of building a clean room occupies a large ratio of the entire cost. Therefore, it is expected that it becomes more and more difficult to build a semiconductor factory including a clean room.